/Engine/Source/Runtime/Engine/Public/Rendering/StaticMeshVertexBuffer.h
Appends the specified vertices to the end of the buffer
void AppendVertices ( const [FStaticMeshBuildVertex](API\Runtime\Engine\FStaticMeshBuildVertex) * Vertices, const uint32 NumVerticesToAppend, bool bUseBackwardsCompatibleF16TruncUVs )